The present invention relates to coil forms, magnetic coils utilizing coil forms, and methods of making the same.
Magnetic coils having a saddle shape, referred to simply as saddle coils, are utilized in devices such as magnetic flowmeters. In a typical magnetic flowmeter, a pair of saddle coils is secured to exterior portions of a cylindrical pipe, through which a fluid passes. One or more electrodes typically extend through the pipe, which generally includes a non-conductive liner, and flow through the pipe is sensed as the fluid moves in a direction generally perpendicular to a primary magnetic field generated by the saddle coils. Such flowmeters are useful for sensing, measuring and controlling industrial processes in industrial process facilities, as well as in other settings.
A typical saddle coil for a magnetic flowmeter is made by wrapping a coil winding about a permanent fixture in a flat (i.e., planar) orientation, then wrapping the winding with a tape or fiberglass material that covers top and bottom portions of the winding. Next, the winding is removed from the fixture and placed over part of a cylinder to bend it to a desired saddle shape. Then a coating on the winding is bonded together to harden the winding in the desired shape. Lastly, the winding assembly is secured to a mounting location on a pipe using conventional threaded mechanical fasteners (e.g., studs, bolts and clamps). The tape (or fiberglass) is utilized because an insulative coating on the wire of the winding is relatively thin, and during use the saddle coil may be exposed to vibrations and other conditions that can wear away the insulative coating and pose a risk of shorting the wire to the pipe on which it is installed. The tape also helps hold the wire of the winding together during bending and bonding operations. However, the tape and clamps utilized in such prior art coils are cumbersome during fabrication.
Therefore, an alternative winding and manufacturing method is desired.